Question

A physics instructor wants to produce a double-slit interference pattern large enough for her class to see. For the size of the room, she decides that the distance between successive bright fringes on the screen should be at least 2.60 cm.

If the slits have a separation d=0.0165mm, what is the minimum distance from the slits to the screen when 632.8-nm light from a He-Ne laser is used?

Answer 1

We have,

Fringe width
Distance between slits
Wavelength of light
Minimum distance from the slits to the screen
Order of the fringe

According to fringe width formula:

Here, we will take because we want to find minimum distance from the slits to the screen,

Therefore, minimum distance from the slits to the screen should be 0.68 m.